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Regulation of Polycystin‐1 C terminal cleavage by Polycystin‐2
Author(s) -
Bertuccio Claudia Alejandra,
Cai Yiqiang,
Somlo Stefan,
Caplan Michael J
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.942.9
Subject(s) - cleavage (geology) , transfection , chemistry , pkd1 , intracellular , cytoplasm , chimera (genetics) , microbiology and biotechnology , fusion protein , blot , biology , polycystic kidney disease , recombinant dna , gene , biochemistry , genetics , kidney , paleontology , fracture (geology)
Autosomal dominant polycystic kidney disease is caused by mutations in PKD1 or PKD2, encoding polycystin‐1 (PC1) and polycystin‐2 (PC2), respectively. PC1 undergoes a cleavage that releases its cytoplasmic C‐terminal tail (CTT), which enters the nucleus. We wished to determine whether PC1 cleavage is influenced by PC2 and, if so, whether the PC2 C terminal domain is involved. We generated a fusion protein in which a chimera of Gal4 and VP16 was inserted downstream of the PC1 intracellular CTT domain. PC1‐GalVP was cotransfected with a Gal4‐driven luciferase reporter gene in COS cells. Cotransfection of PC1 and PC2 produced a 2‐fold increase in luciferase activity compared to cells expressing PC1 alone. Western blotting revealed increased PC1 CTT cleavage in the presence of PC2. Luciferase activity did not increase in cells transfected with PC1 and PC2 L703X (lacking a portion of the PC2 C‐terminal). We analyzed a series of truncated PC2 constructs and found that, in contrast to PC2 L703X, PC2 constructs that terminate at residues R742, E787, D847, K859, or R872 stimulated PC1 CTT cleavage to the same extent as full‐length PC‐2. Surprisingly, the A753X and G821X truncated constructs appear to increase PC1 CCT cleavage beyond the levels obtained with full‐length PC2. Thus, the release of the CTT from PC1 is influenced by PC2 and may be regulated by sequences contained within the PC2 C terminal tail. Support by NIH 57328